This invention relates to an attachment device for the straw walkers of a combine harvester.
Combine harvesters of the conventional type include a cylinder which receives the harvested crop and acts initially to cut the straw of the crop and to separate the seed materials and chaff from the straw. The cylinder does not complete the separation process and accordingly the straw is dumped upon a set of straw walkers which move the chopped straw rearwardly from the feed end of the straw walkers toward a rear discharge end with the straw being agitated to cause the seed material to drop from the straw for collection and separation in a further part of the combine.
Conventionally each of the straw walkers comprises a pair of separate vertical plates with a transverse web between the plates. The upper edge of each of the plates is cut into a sawtooth configuration. The web is perforated. The whole straw walker is mounted upon a pair of crank elements which move the straw walker in an orbital motion so that it moves upwardly, rearwardly, downwardly, and forwardly. Adjacent straw walkers are arranged to be substantially in opposite phase so that as one moves forwardly the other is moving rearwardly. In this way, the straw is lifted and then moved rearwardly by its engagement with the sawtooth edges. This agitation also causes the seed material to drop out of the straw and fall onto the webs and then through the perforations for collection and further separation in a different part of the combine.
Careful study of conventional combines will however show that straw walkers are somewhat inefficient so that much of the seed material remains in the straw as it is discharged from the rear end and is thus lost causing significant reduction in yields.